1. Field of the Invention
The present invention relates to an improved leak-proof construction and the rotating shaft attaching means for an oil-containing bearing, particularly, such a bearing having a plurality of oil-storing grooves in a spaced circumferential arrangement, two oil guiding holes for increasing the lubrication effect between the rotating shaft and the bearing, and an oil-guiding plate for preventing lubricant oil leakage provided on the rotating shaft. Also, an insert block and a bearing socket with a central groove or protrusions and mounted on an end part of the rotating shaft extending out of the bearing reduces the noise during rotation of the shaft by forming wedge film, such that an oil film will be generated between the bearing socket and the oil containing bearing to reduce axial friction forces therebetween.
2. Description of the Prior Art
An oil-containing bearing used in a conventional system is shown in FIGS. 1A and 1B which are views showing the construction of a bearing in a venting fan used for cooling electronic equipment. It can be seen from FIG. 1B, the component members of the bearing 100 installed in this fan and from FIG. 1C the structure of the aforementioned conventional oil-containing bearing, wherein at the end portion of the rotating shaft 102 extending out of the oil containing bearing 101 in a downward direction, there are provided C-clip 103, an O ring 104 and a washer 105 respectively. The front end of the oil containing bearing 101 is further provided with a seal 106. The O ring 104 is sandwiched between the C-clip 103 and the washer 105 and pressed against the end portion of the rotating shaft 102. However, the O ring is made of the usual rubber material and has an extremely high friction coefficient. A friction force is produced when the O ring is pressed tightly against the end portion of the rotating shaft by the washer 105 and the C-clip 103 resulting in an impedement for the rotation of the rotating shaft. The above disadvantage not only increases the power loss (w) of the shaft, but also increases the noise of rotating shaft during its rotation. It is known that in manufacturing conventional oil containing bearing, after the process of powder casting, the bearing must be sintered so as to obtain considerable machinery strength. While in the process of sintering, there are two conditions which cause the formation of holes: 1) the remaining spaces between particles (as shown in FIG. 4A); 2) the holes originally occupied by metal particles of low melting point (as shown in FIG. 4B). The temperature for the sintering oil containing bearings of copper families is about 700.degree. C.-800.degree. C. It is known that there is 9-11% of tin in copper families materials, however, the melting point of tin is 232.degree. C., while that of copper is 1083.degree. C. As the copper is sintered in 700.degree. C.-800.degree. C., the spaces originally occupied by the low melting point tin are formed as oil containing holes for containing lubricant oil (as shown in FIG. 4C). Thus when the shaft 102 is rotating in self-lubricated bearing 101, the capillary action (as shown in FIG. 5) as well as the heat generated from friction, causes the lubricant oil to permeate out of the oil containing holes in the bearing for lubricating the shaft (as shown in FIG. 6). However, the continuous rotation of the shaft causes the oil to brim over the oil-containing holes out of the portion in contact with the rotating shaft (as shown in FIG. 1D). The lubricant oil inside selflubricated bearing then permeates out of the rotation shaft continuously. In this condition, the lubricant oil leaking out of the bearing not only pollutes the electric elements, but also shortens the life of the bearing because of the loss of lubricant oil. These are the defects which most often occur in known self-lubricated bearings. Furthermore, the combination of an oil-containing bearing and a rotation shaft containing an O-ring, consumes rotational energy due to frictional forces generated during rotation of shaft. There is a known combination without an O-ring, however, this combination of oil-containing bearing and rotation shaft cannot reduce the above-mentioned friction force generated between the bearing and the washer during relative motions. Moreover, there is no buffering effect against axial forces.